Also, I'm not sure the size of each duplex unit your are buying, but it is probably at least a 2/1 unit, and I'm guessing with your GF that you won't be renting the other room, so in a way, her paying rent to you is like if you were renting that room out.    

The three different units of of different size and number of beds.

Size of the units.

Good size, good yard, and the ever present "needs some TLC" in the listing. 

By population growth, landlord friendliness, city size (I LOVE big cities), economic diversity, my budget and a few other factors.So Indianapolis is one of my winners which I am looking into more seriously. 

Given the initial investment required to purchase and rehab the note sizes discussed in this thread, what do you feel is a solid SDIRA starting balance for a beginner note investor with limited knowledge in this arena?

Many jurisdictions do it by density, so you need to combine the zone name with the lot size to figure out how many units are possible. 

I'm also sure that not everyone agrees with me, but, I haven't written any books on communities or anything in manufactured housing although I have published a newsletter and written many white papers used throughout the industry.When considering the size of someone's community operation, remember that none of the largest operators in the country that were huge in the 1960s-1980s are still around as the largest of operators.

You don't state what the price is, age of house, size of lot, condition of house, or anything else.I will tell you the first thing you should do is get to KNOW your market, and local values.

Your value is really determined by location here and the size of the lot.Nashville changed the building codes 2 years ago and it allowed you to take a side yard and build a house on it.